Method and apparatus (discontinuous imperforate portions on backing means of open sandwich)

ABSTRACT

A method and apparatus for producing, from a layer of fibrous material such as a fibrous web, nonwoven fabrics that contain apertures or holes, or other areas of low fiber density, and have a plurality of patterns that alternate and extend throughout the fabric. One form of the method includes the steps of supporting the starting web upon a backing means that is foraminous except for a discontinuous pattern of imperforate portions and has protuberances and troughs alternating across its foraminous portions, then directing fluid rearranging forces substantially uniformly and continuously across the surface of the web, causing some of the fluid streams to strike the imperforate portions of the backing means, and others to strike the protuberances on the backing means, to deflect the same, all of the fluid streams ultimately passing through the foraminous portions of the backing means. Each discontinuous imperforate portion extends along the surface of the backing means in each direction a distance at least about twice the horizontal distance between the bottoms of a pair of immediately adjacent troughs. Each pair of immediately adjacent discontinuous imperforate portions spans between them at least one protuberance and a trough on each side of the protuberance. The imperforate portions of the backing means may rise above the foraminous portions. The resulting fabric consists of fibers that have been rearranged to provide a first pattern of holes or other areas of low fiber density corresponding to the imperforate portions of the backing means, and a second pattern corresponding to protuberances on the foraminous portions of the backing means.

United States Patent [1 1 Kalwaites Aug. 7, 1973 METHOD AND APPARATUS(DISCONTINUOUS IMPERFORATE PORTIONS ON BACKING MEANS OF OPEN SANDWICH)[75] Inventor: Frank Kalwaites, Gladstone, NJ.

[73] Assignee: Johnson & Johnson, New Brunswick,

22 Filed: Feb. 10, 1972 21 Appl. No.: 225,263

Related U.S. Application Data [63] Continuation of Ser. No. 22,313,March 24, 1970,

Primary ExaminerDorsey Newton Attorney-Robert L. Minier and Leonard P.Prusak [57] ABSTRACT A method and apparatus for producing, from a layerof fibrous material such as a fibrous web, nonwoven fabrics that containapertures or holes, or other areas of low fiber density, and have aplurality of patterns that alternate and extend throughout the fabric.One form of the method includes the steps of supporting the starting webupon a backing means that is foraminous except for a discontinuouspattern of imperforate portions and has protuberances and troughsalternating across its foraminous portions, then directing fluidrearranging forces substantially uniformly and continuously across thesurface of the web, causing some of the fluid streams to strike theimperforate portions of the backing means, and others to strike theprotuberances on the backing means, to deflect the same, all of thefluid streams ultimately passing through the foraminous portions of thebacking means. Each discontinuous imperforate portion extends along thesurface of the backing means in each direction a distance at least abouttwice the horizontal distance between the bottoms of a pair ofimmediately adjacent troughs. Each pair of immediately adjacentdiscontinuous imperforate portions spans between them at least oneprotuberance and a trough on each side of the protuberance. Theimperforate portions of the backing means may rise above the foraminousportions. The resulting fabric consists of fibers that have beenrearranged to provide a first pattern of holes or other areas of lowfiber density corresponding to the imperforate portions of the backingmeans, and a second pattern corresponding to protuberances on theforaminous portions of the backing means.

3 Claims, 10 Drawing Figures PATENTED M18 7 I975 SHEEI 2 BF 4 INVENTORFKAWK K44 wan-'5 ATTORNEY P'ATENTEB lug 7 B13 SHEET l 0F 4 INVENTOR FR KKALW/MTES 'rw flw ATTORNEY LIA.

METHOD AND APPARATUS (DISCONTINUOUS IMPERFORATE PORTIONS ON BACKINGMEANS OF OPEN SANDWIC This is a continuation application of myco-pending application Ser. No. 22, 313, filed Mar. 24, 1970, nowabandoned.

This invention relates to a method and apparatus for the production ofnonwoven fabrics, and more particularly to a method and apparatus forthe production of nonwoven fabrics from a layer of fibrous material suchas a fibrous web, in which the individual fiber elements are capable ofmovement under the influence of applied fluid forces, to form a fabricthat contains rearranged fibers defining a plurality of patterns ofapertures or holes, or other areas of low fiber density, that alternateand extend throughout the fabric. Some of the rearranged fibers in thefabric lie in yarn-like bundles of closely associated and substantiallyparallel fiber segments that help to define the apertures (holes) orother areas of low fiber density contained in the fabllC.

BACKGROUND OF THE INVENTION Various methods and apparatus formanufacturing apertured nonwoven fabrics involving the rearrangement offibers in a starting layer of fibrous material have been known for anumber of years. Some of these methods and apparatus for the manufactureof such fabrics are shown and described in US. Pat. No. 2,862,251, whichdiscloses the basic method and apparatus of which the present inventionis a specific form, and in US. Pat. Nos. 3,081,500 and 3,025,585.

The nonwoven fabrics made by the methods and apparatus disclosed in thepatents just mentioned contain apertures or holes or other areas of lowfiber density, out-lined by interconnected yarn-like bundles of closelyassociated and substantially parallel fiber segments. (The term areas oflow fiber density" is used in this specification and claims to includeboth (1) areas in which relatively few fibers are found in comparison tothe rest of the fabric, and (2).apertures (holes) that are substantiallyor entirely free of fibers.)

One of the specific known methods for producing rearranged nonwovenfabrics is to support a loose fibrous web or layer upon a permeablebacking member that has protuberances or tapered projections" spacedacross its surface, with troughs or low areas between the protuberances.Streams of rearranging fluid are applied substantially uniformly andcontinuously over the entire surface of the loose fibrous web or layer,and after the streams pass through the fibrous material some of themstrike the protuberances on the backing means and are diverted insidewise directions to cause fiber segments to move from the areaadjacent the high point of each protuberance into the immediatelyadjacent troughs. All the streams then pass through the openings in thepermeable backing means and leave the rearranging zone.

The effect of these fluid rearranging forces is to pack groups of fibersegments into interconnected yarnlike bundles of closely associated andsubstantially parallel fiber segments and to position them in thetroughs on the backing means so as to define a pattern of areas of lowfiber density throughout the resulting nonwoven fabric.

In this prior art method, the backing member is uniformly permeablethroughout its area in order to provide an unimpeded route by which thestreams of rearranging fluid can be quickly carried away after they havemoved fiber segments from the protuberances into the troughs of thebacking means. Care is always taken in any fluidrearrangement to avoidloss of web identity through flooding (US. Pat. No. 2,862,251, col. 2,line 60 to col. 3, line 12), and with the specific prior art methodunder discussion it is said to be essential that the backing member bepermeable to the passage of fluid from the applied streams, so that thefluid may pass freely through the backing member and away from the layerof fibers rather than having some or all of the fluid reflected back inthe same general direction from which it is applied (U.S. Pat. No.3,025,585, col. 2, lines 38-48).

The fiber segments rearranged by the prior art method referred to aremoved laterally only as indicated, which is no farther than from thehigh point of a protuberance to the low point of an immediately adjacenttrough. This will usually be about one-half the horizontal distance fromthe bottom of one trough or low point to the bottom of the next.

SUMMARY OF INVENTION l have now discovered that, unexpectedly, one canblock off substantial portions of the otherwise permeable backing orsupport member in the prior art method just described, to interrupt andimpede the flow of rearranging fluid through the backing member, andstill not impede satisfactory rearrangement of the fibers of the fibrousstarting material by the protuberances on the backing means into anonwoven fabric containing yarn-like bundles of fiber segments andhaving well defined apertures in a plurality of patterns that alternateand extend throughout the fabric. Moreover, contrary to the prior artmethod, the fiber segments that are rearranged into yarn-like bundles ofclosely associated and substantially parallel fiber segments are movedlaterally for a distance substantially greater than the distance betweenthe high point of a protuberance and the bottom of its immediatelyadjacent trough or low point.

In the practice of this invention, the starting material is a layer offibrous material whose individual fibers are in mechanical engagementwith one another but are capable of movement under applied fluid forces.The layer of fibrous starting material is supported in a fiberrearranging zone that has an entry side and an exit side and in whichfiber movement in directions parallel to the plane of the fibrousmaterial is permitted in response to applied fluid forces. The fiberrearranging zone is subdivided into barrier regions that are arranged ina discontinuous pattern, and deflecting regions that are continuous andlie between and interconnect the barrier regions.

Streams of rearranging fluid, preferably water, are projected into thefibrous starting material substantially uniformly and continuouslyacross its surface, in a direction perpendicular to the fibrous layer atthe entry side of the rearranging zone. The streams of rearranging fluidare comprised of three categories first portions that pass through thedeflecting regions of the rearranging zone, second portions that passthrough the barrier regions, and third portions that pass through thedeflection regions but in a different manner than the first portions.

The first portions of the rearranging fluid are passed through theinitial part of the deflecting regions, as the layer of fibrous startingmaterial lies in said regions, toward a plurality of dispersal points inthe deflecting regions lying adjacent the exit side of the rearrangingzone. Each of these dispersal points is surrounded by fiber accumulatingzones. At least one dispersal point and its associated fiberaccumulating zones lie between each barrier region and its adjacentbarrier regions at all points around the perimeter of the firstmentioned barrier region.

At each dispersal point, the first portions of rearranging fluid aredeflected diagonally and downwardly away from the perpendiculardirection of their entry into the rearranging zone, and are moved intothe area immediately surrounding the dispersal point. This movement ofthe rearranging fluid moves fiber segments lying adjacent the dispersalpoint into the area around that point, and positions them there inyarn-like bundles of closely associated and substantially parallel fibersegments. Some of these yarn-like bundles lie in fiber accumulatingzones that are located in peripheral portions of the deflecting regions,and some lie in accumulating zones that are located between immediatelyadjacent dispersal points.

The second portions of rearranging fluid are passed through the parts ofthe layer of fibrous starting material that lie in the barrier regionsof the fiber rearranging zone, and cause movement of at least somesegments of the fibers in those regions transverse to the direction oftravel of the projected streams. At the exit side of the rearrangingzone, the passage of these second portions of rearranging fluid out ofthe parts of the fibrous layer that lie in the barrier regions isblocked, and the fluid is deflected sidewise into the deflecting regionsof the rearranging zone. This movement of the rearranging fluid movesfiber segments that lie in the barrier regions into at least some of theyam-like bundles of closely associated and substantially parallel fibersegments mentioned above.

The first and second portions of the rearranging fluid that have beendeflected as described are then actively mingled, and the intermingledfluid is passed out of the fiber rearranging zone through spaced exitsin the deflecting regions at the exit side of the rearranging zone. Atthe same time, third portions of fluid are intermingled with the firstand second portions, to be passed out of the same exits. The thirdportions of fluid are projected into the fibrous starting material andare moved to the exits referred to without passing through a dispersalpoint or a barrier region.

To assist in moving all the rearranging fluid through the layer offibrous starting material and in rearranging the fiber segments of thatlayer, a vacuum is applied at the exit side of the fiber rearrangingzone.

The result of application of the fluid rearranging forces just describedis to form a nonwoven fabric having yarn-like bundles of fiber segmentsthat define a first pattern of areas of low fiber density arranged inaccordance with the pattern of arrangement of the barrier regions of therearranging zone, and a second pattern of areas of low fiber densityarranged in accordance with the pattern of arrangement of the dispersalpoints in the deflecting regions of the fiber rearranging zone.

In one form of the method and apparatus of this invention, the fibrousstarting layer is supported on backing means having imperforate portionsarranged in a discontinuous pattern, with continuous foraminous portionslying between and interconnecting the imperforate portions. Thecontinuous foraminous portions of the backing means have protuberancesand troughs alternating across the surface of such portions in both thelongitudinal and transverse directions.

Each discontinuous imperforate portion extends along the surface of thebacking means in each direction for a distance at least about twice thehorizontal distance from the bottom of one of said troughs in theforaminous portion of the backing means to the bottom of the troughimmediately adjacent and parallel to it. This doubles the averagedistance fiber segments must be moved laterally to bring them intoyarn-like bundles in adjacent troughs of the backing means. By the sametoken, it multiplies by four times the quantity of fluid that must bedisposed of in any area lying between adjacent troughs, while increasingby only two times the perimeter of that area out of which the fluidflows in order to leave the rearranging zone.

Each imperforate portion of the backing means may, if desired, riseabove the plane of the tops of the foraminous portions of the backingmeans, with the central portions of the imperforate member rising higherthan the edge portions thereof. However, it is not necessary that theimperforate portions constitute tapered projections as in the prior artmethod mentioned above, and if desired they may even be flush with thetops of the foraminous portions of the backing means and fiberarrangement is still achieved.

In the practice of this invention, streams of rearranging fluid,preferably water, are applied substantially uniformly and continuouslyacross the surface of the layer of fibrous starting material as it issupported on the backing means just described. The streams pass throughthe fibrous layer and strike the backing or support means, some strikingthe imperforate portions of thebacking means and others striking theprotuberances on the foraminous portions of the backing means. In eithercase, the streams are deflected in sidewise directions and join otherstreams of rearranging fluid that pass through the openings of thecontinuous foraminous portions of the backing means without striking thebacking means.

To assist in moving the rearranging fluid through the layer of fibrousstarting material and in rearranging the fibers of that layer, a vacuumis applied on the opposite side of the backing means from the fibrousstarting material.

As the various streams of rearranging fluid follow their coursesdescribed, they cause fiber segments that overlie the protuberances onthe foraminous portions of the backing means to move into troughs lyingbetween those protuberances, and to be positioned there in yarn-likebundles of closely associated and substantially parallel fiber segments.At the same time, other streams of rearranging fluid cause fibersegments that overlie the discontinuous imperforate portions of thebacking means to be moved into surrounding areas of the fibrous layer,where they are also consolidated into yarn-like bundles of fibersegments, in troughs located in peripheral portions of the foraminousportions of the backing means.

The resulting nonwoven fabric has a first pattern of areas of low fiberdensity, defined by yarn-like bundles of fiber segments, thatcorresponds to the pattern of the discontinuous imperforate portions ofthe backing means. In addition, thefabric has a second pattern of areasof low fiber density, defined by yarn-like bundles of fiber segmentspositioned in the troughs between adjacent protuberances on theforaminous portions of the backing means, that corresponds to thepattern of the protuberances on those foraminous portions of the backingmeans.

The fibrous starting material used with the method and apparatus of thisinvention is comprised of closely intertwined and interentangled fibersarranged (depending on the degree of fiber orientation in the layer) ina more or less helter-skelter fashion. When streams of rearranging fluidare projected against such a fibrous material supported on partiallyimperforate backing means of the kind employed in this invention, onewould expect that the streams would simply mat the interentangled fibersdown against the imperforate portions of the backing means, so thatthere would be no fiber rearrangement produced there at all. This effectwould be expected to be even more pronounced when each discontinuousimperforate portion of the backing means is of such asize that itextends in each direction along the surface of the backing means for adistance atleast twice the horizontal distance between immediatelyadjacent troughs on that surface, for in that situation the streams ofrearranging fluid would strike an even greater obstacle to a rapid exitfrom the fiber rearranging zone.

Surprisingly, it has been found that obstructing the flow of fluidrearranging streams away from the rearranging zone by providingdiscontinuous imperforate portions of substantial size in the backingmeans does not have any undesirable result, nor prevent the productionof excellent apertured rearranged nonwoven fabrics having a plurality ofpatterns extending throughout the fabric.

FURTHER DESCRIPTION OF INVENTION The basic method and apparatus of thisinvention are shown and described fully in my U.S. Pat. No. 2,862,25l,issued Dec. 2, 1958. Full particulars of the basic invention asdisclosed in that patent are incorporated in this application byreference, although some of those particulars are repeated here. Inaddition, the specific feature peculiar to the method and apparatus ofthe present invention which is the provision of discontinuous barrierregions (defined, for example, by spaced imperforate members on abacking means) to block and deflect portions of the streams ofrearranging fluid at the exit side of a fiber rearranging zone theremainder of which is comprised of continuous deflecting regionsincluding dispersal points surrounded by fiber accumulating zones (forexample, foraminous portions of a backing means having alternatingprotuberances and troughs) is described in detail in this application.

Starting material. The starting material used with the method orapparatus of this invention may be any of the standard fibrous webs suchas oriented card webs, isowebs, air-laid webs, or webs formed by liquiddeposition. Thewebs may be formed in a single layer, or by laminating aplurality of the webs together. The fibers in the web may be arranged ina random manner or may be more or less oriented as in a card web. Theindividual fibers may be relatively straight or slightly bent. Thefibers intersect at various angles to one another such that, generallyspeaking, the adjacent fibers come into contact only at the points wherethey cross. The fibers are capable of movement under forces applied byfluids such as water, air, etc.

To produce a fabric having the characteristic hand and drape of atextile fabric, the layer of starting material used with the method orapparatus of this invention may comprise natural fibers such as cotton,flax, etc.;

mineral fibers such as glass; artificial fibers such as viscose rayon,cellulose acetate, etc.; or synthetic fibers such as the polyanides, thepolyesters, the acrylics, the polyolefins, etc., alone or in combinationwith one another. The fibers used are those commonly considered textilefibers; that is, generally fibers having a length from about inch toabout 2 to 2% inches.

Satisfactory products may be produced in accordance with this inventionfrom starting webs weighing between grains per square yard to 2,000grains per square yard or higher. With heavier web weights, as discussedbelow, the difference in elevation between the dispersal points and thefiber accumulating zones in the deflecting region of a fiber rearrangingzone (for example, the protuberances and troughs, respectively, on theforaminous portions of a backing means) must be more pronounced in orderto achieve the bundling that is a necessary part of this invention.

Continuous foraminous portions of backing means. As already indicated,in one form of this invention a backing means is employed that hasimperforate portions arranged in a discontinuous pattern to providebarrier regions in the fiber rearranging zone, with con tinuousforaminous portions lying therebetween. The continuous foraminousportions of the backing means are provided throughout their surfaceswith a plurality of protuberances and troughs alternating across thosesurfaces, and thus comprise deflecting regions containing dispersalpoints each of which is surrounded by fiber accumulating zones.

As illustrated in the drawings below, for improved results the tops ofthe protuberances on the foraminous portions of the backing means riseabove the bottoms of the immediately adjacent troughs by a distanceequal to at least about three times the average diameter of the fibersin the layer of fibrous starting material or at least 0.005 inch.Preferably, the distance is equal to about ten times the averagediameter of those fibers, especially when the web weight of the fibrousstarting material is of the order of 800 grains per square yard orhigher. It also becomes more important to have prominent protuberanceson the continuous foraminous portions of the backing means the greateris the area of the discontinuous imperforate portions of the backingmeans, since a large imperforate portion increases the number of loosefiber ends that will be washed off those imperforate portions to beadded to the fibrous web already lying above the foraminousportions ofthe backing means.

The fibrous starting material used with the method and apparatus of thisinvention is comprised of closely intertwined and interentangled fibersarranged (depending upon the degree of fiber orientation in the layer)in a more or less helter-skelter fashion. Some of the fibers of thestarting material will by random chance lie generally parallel to thetroughs on the continuous foraminous portions of the backing means overwhich they lie, but the great majority of the fibers will lie at anangle to the longitudinal axes of the troughs, and a substantial numberof these will lie at angles of 45 or more to such an axis.

In the practice of this invention, the movement of fiber segments intocloser association and substantial parallelism with each other inyarn-like bundles in the troughs on the continuous foraminous portionsof the backing means is more likely to occur with those fiber segmentsin the starting material that already lie only a relatively few degreesaway from a position parallel to the longitudinal axis of a trough. Toput it the other way, this type of movement is more difficult thegreater the angle between a given fiber segment and the axis of thetrough, and when fiber segments lie at too great an angle to thelongitudinal axis of a trough, they simply continue to lie at thatangle, matted down against the backing means by the force of therearranging fluid. For the greater the angle between the fiber segmentand the trough axis, the shorter is the portion of the fiber thatbridges the trough, and the more difficult it is for the rearrangingfluid forces to get a purchase" on the fiber segment to turn it aroundinto a position parallel with the trough axis.

Likewise, the narrower the troughs are on the foraminous portions of thebacking means, the more difficult it is for the rearranging fluid forcesto get a purchase" on the short portion of the fiber segment thatbridges the trough, to swing that segment around into a positionparallel to the axis of the trough, to be consolidated there to form ayarn-like bundle with other similarly positioned fiber segments. Theforce of the vacuum assist employed with this invention is of courseadded to the force of the other rearranging fluid. with the use of avacuum assist, the distance between immediately adjacent protuberanceson the backing means, which determines the width of a trough from thetop of one side to the other, is ordinarily equal to at least abouttimes the average diameter of the fibers of the fibrous startingmaterial. or at least 0.025.

The minimum spacing of protuberances just mentioned, which affects thewidth of the troughs lying between immediately adjacent protuberances,also assists in providing good visual resolution between variousyarn-like bundles of fiber segments in the fabric resulting from thepractice of this invention. For if the protuberances are too closelyspaced and the troughs between them are too narrow, yarn-like bundles offiber segments may be accumulated in the troughs but will not bediscernible one from the other, because each one merges into the nextadjacent similar bundle of fiber segments. If the web weight of thefibrous starting material is high, the distance between immediatelyadjacent protuberances on the foraminous portions of the backing meansshould be increased, or otherwise the yarn-like bundles of fibersegments will be masked out by the same merging phenomenon justmentioned.

The continuous foraminous portions of the backing means are sufficientlywide that, with the appropriate web weight in the starting material,good formation of yarn-like bundles of fiber segments can be effectedabove those foraminous portions. Thus, each continuous foraminousportion has a width-at its narrowest part sufficient to include at leastone protuberance and a trough on each side of the protuberance. Thisminimum width for each continuous foraminous portion of the backingmeans produces a minimum of one well defined hole or other area of lowfiber density corresponding to the protuberance on the backing means,with yarn-like bundles of fiber segments positioned in the troughssurrounding the protuberance.

There is no maximum limit on the width of the foraminous portions ofthebacking means. That dimension is determined only by the pattern desiredin the nonwoven fabric to be produced. Thus, the width of a continuousforaminous portion may be as much as five or 10 times the horizontaldistance between adjacent troughs, or even more.

The foraminous portions of the backing means used in this invention areof sufficient size to occupy together at least about 10 percent, andpreferably about 30 percent or more, of the total area of the backingmeans.

Discontinuous imperforate portions of backing means. In plan view, thediscontinuous imperforate portions of the backing means may have anyshape desired i.e., circular, oval, diamond, square, crescent, halfmoon, lace-like, free form, etc.

Each discontinuous imperforate portion of the backing means extendsalong the surface of the backing means a distance equal to at leastabout two times, and preferably three times, the horizontal distancefrom the center of one of the troughs on the backing means (i.e., afiber accumulating zone) to the center of the trough immediatelyadjacent and parallel to it. If desired, this dimension of adiscontinuous imperforate portion may be as much as five times thehorizontal distance between the center of adjacent troughs, or evenmore.

The maximum dimension of each discontinuous portion may be greater thanthe average length of the fibers in the fibrous starting material, andall the fibers may still be moved off those imperforate portions intosurrounding areas of the fibrous layer. However, the larger thedimensions of the discontinuous imperforate portions of the backingmeans, the more likely it is that some fiber segments will not be movedoff those imperforate portions during fiber rearrangement but willremain there to lie in areas of low fiber density in the resultingfabric that correspond to the discontinuous imperforate portions of thebacking means. Control of fiber movement is thus more effective if themaximum dimension of each discontinuous imperforate portion issubstantially less than the average fiber length, for example, not morethan 1 inch maximum dimension, and preferably not more than 1 inch to kinch maximum dimension, when fibers having an inch-and-a-half staplelength are employed.

lf one dimension of a discontinuous imperforate portion of the backingmeans is made smaller, the other may be increased. If the imperforateportion is longer than it is wide, and the longer dimension extends inthe direction of fiber orientation in the layer of fibrous startingmaterial, fiber segments will be moved off the imperforate portion morereadily. On the other hand, if the larger dimension of such animperforate portion of the backing means extends perpendicular to thedirection of fiber orientation, there will be more tendency for bridgingof fibers across the imperforate portion of the backing means to occur.

Improved results are obtained if each discontinuous imperforate portionof the backing means, whatever its precise shape may be, is a fairlycompact area having a maximum dimension not much greater than itssmallest dimension. Thus, improved results are produced if the maximumdimension of each discontinuous imperforate portion is no greater thanabout four times its minimum dimension and still further improvement isproduced if the maximum dimension is no more than about one-and-a-halftimes the minimum dimension of each such portion.

In any event and regardless of all other factors, all loose ends offibers in the layer of fibrous starting material that are positionedabove the imperforate portions of the backing means will be washed offthose imperforate portions by the fluid rearranging forces applied tothe fibrous material.

The discontinuous imperforate portions of the backing means may be flushwith the plane of the top surfaces of the foraminous portions of thebacking means,

but for improved results they rise at least by about one sixty-fourthinch above the plane of that surface, and preferably by about onethirty-second inch or onesixteenth inch for starting fibrous webs havingweb weights in the range of from about 100 to about 1,000 grains persquare yard. The height of the imperforate portions may be even greaterwithout interfering with fiber rearrangement, but too great a height forthese members may interfere with removal of the rearranged fabrics.

When relatively heavy starting webs of fibrous material are employed, agreater height for the discontinuous imperforate portions of the backingmeans produces clearer formation of areas of low fiber density in theresulting fabric. In other words, increased height for the discontinuousimperforate portions produces more pronounced formation of yam-likebundles of fiber segments at the periphery of the areas of low fiberdensity which are formed in the resulting fabric above the imperforateportions of the backing means.

The discontinuous imperforate portions of the backing means should havewalls that are vertical or taper out in a downward direction. The edgesare preferably slightly rounded, but not excessively so. In any case,the top of the discontinuous portions should be smooth, in order not tointerfere with fiber rearrangement.

Rearranging fluid. The rearranging fluid for use with this invention ispreferably water or similar liquid. It may also be other fluids such asa gas, as described in my US. Pat. No. 2,862,251.

Application of vacuum. The vacuum applied to the opposite side of thebacking means simultaneously with the application of fluid rearrangingforces to the fibrous starting layer is of the order of about 1 inch toabout 4 inches of mercury, preferably about 2 inches of mercury. I

Additional vacuum may be used to advantage after the rearranged fabrichas moved out of the rearranging zone, in order to help remove excessliquid from the fabric before the fabric is removed from tha backingmeans.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fullydescribed in connection with the accompanying drawing, in which:

FIG. 1 is a diagrammatic showing in elevation of one type of apparatusthat may be employed in the present invention.

FIG. 2 is an enlarged diagrammatic plan view of a portion of a backingmeans that can be used in the apparatus of FIG. 1.

FIG. 3 is a cross sectionalview taken'along the line 3-3 of FIG. 2.

FIG. 4 is an enlarged fragmentary diagrammatic plan view of one of theforaminous portions of the backing means of FIG. 2.

FIG. 5 is a cross sectional view taken along line 5-5 of FIG. 4.

FIG. 6 is a cross sectional view taken along line 6-6 of FIGS. 4 and 5.

FIG. 7 is a schematic perspective representation of the paths followedby various streams of rearranging fluid as they pass through theforaminous member shown in FIGS. 4 through 6.

FIG. 8 is a schematic plan representation of the paths followed by thestreams of rearranging fluid shown in perspective in FIG. 7.

FIG. 9 is a photograph of a nonwoven fabric made in accordance with thepresent invention, shown in the original drawing at actual size.

FIG. 10 is a photomicrograph of the nonwoven fabric of FIG. 9, shown atan original enlargement of fibe times.

DETAILED DESCRIPTION OF SPECIFIC FORM OF THE INVENTION FIG. 1 shows oneform of apparatus that may be used in accordance with the presentinvention.

In this apparatus, horizontal frame members 2 are supported by legs 3and 4. At the feed end of the machine (on the left hand side of FIG. 1),a pair of vertical frame members 5 extend upwardly above horizontalframe members 2, with a pair of wet-out rolls 6 and 7 rotatably mountedbetween them. Wet-out roll 6 is partially immersed in a water pan 8, andits shaft 9 is journalled in bearings (not shown) fixed to verticalframe members 5. Bearings 10, in which shaft 11 of wet-out roll 7 isjournalled, are slidably mounted on vertical frame members 5.

The vertical position of wet-out roll 7 is adjustable, and is regulatedby hydraulic positioning cylinders 13 mounted on the top of eachvertical frame member 5. In this way, the pair of wet-out rolls 6 and 7cooperate to control the moisture content of a web or layer of fibrousmaterial, of a type such as mentioned above as being a suitable startingmaterial, which is fed through the nip between the wet-out rolls.Preferably the moisture content of the layer of fibers as it is movedfrom the wet-out rolls is in the neighborhood of from 109 to 200percent. (The term percent moisture," when used in this specification,refers to percentage of moisture by weight of the dry web.)

The layer of fibers moves from the nip of the wetout rolls to the fiberrearranging zone of the apparatus to effect the rearrangement of thefibers in the starting web or layer 15, to produce a rearranged fibrousweb or layer 15' having a plurality of patterns of holes or other areasof low fiber density as described above. Thus the starting layer offibers moves from the wet-out rolls to be supported on a backing meansin the form of endless belt 16 (to be described in detail below), whichextends around a pair of parallel rolls 17, 18 rotatably mountedadjacent opposite ends of the frame. Each of the rolls 17, 18 is mountedon a shaft 19, the ends of which are journalled in bearings 20 carriedon horizontal frame members 2. Conventional driving means (not shown)are connected to either one of shafts 19.

A water pipe 21, mounted in any suitable manner, supports a pair ofheaders 22 above the upper reach of endless belt 16. Each header extendstransversely of belt 16, and has a row of jet nozzles 23 to providewater sprays across the width of that belt.

A pair of suction boxes 24 are mounted on and extend transversely acrossframe members 2 between the rolls l7 and 18 which carry endless belt 16,with one of the boxes located directly beneath each row of jet nozzles23. Each suction box is closed on all sides except for an opening 25 towhich a vacuum line 26 is connected, and a slot or group of perforations27 which extend across top wall 28 of the suction box. The top wall ofeach suction box is positioned adjacent the underside of the upper reachof endless belt 16.

Nonwoven fabric 15', after rearrangement but before reaching theposition where endless belt 16 starts to track around roll 18, is liftedoff the belt by causing it to pass upwardly and over a horizontalcylindrical doffing member 290 which extends transversely of the machineand is supported at its ends in the side frames. The fabric then passesdownwardly and around through the nip between guide rolls 29b and 29c onits way to a suitable drying area (not shown). Guide rolls 29b and 29care parallel to doffing member 290, and like it are supported at theirends in the side frame members of the machine.

Backing means. Endless belt or backing means 16, as shown in FIG. 2, hasa continuous pattern of foraminous portions 30 and a discontinuouspattern of imperforate portions 31. In FIG. 2, the imperforate portionsare round and arranged such that four of them lie in a square patternover the surface of the backing means, the remainder of the member beingforaminous. As already indicated above, the imperforate portions of thebacking member may have any shape desired. They may also be arranged inany discontinuous pattern over the backing means; i.e., they may bealigned longitudinally and/or transversely, staggered, etc.

FIG. 3 shows a cross section of the backing means of FIG. 2. As seen,each discontinuous imperforate portion 31 of backing means 16 has acurved top surface that rises slightly above the top surface offoraminous portions 30 of the backing means. Because of the curved topsurface, central portion 32 rises above edge portions 33 ofdiscontinuous imperforate portions 31 of the backing means. Extreme edgeportions 34 are slightly rounded.

Foraminous portions 30, as shown in FIGS. 4 through 6, are formed of acoarse woven screen, preferably metal. In the embodiment shown, wires 40running vertically in FIG. 4 are straight, while wires 41 runninghorizontally in that figure weave alternately over and under wires 40.Protuberances 42 are present throughout foraminous portion 30 as thetopmost part of each knee" of a given strand 41 of the screen that isformed as the strand weaves over and under the strands 40 that lieperpendicular to it.

As a given strand 41 slants downward to pass under a strand 40perpendicular to it, it crosses two other strands 41 disposed on eitherside of it, as those strands slant upward to pass over the sameperpendicular strand that the given strand will pass under. Each seriesof such crossing points" 43 forms a trough, such as trough 44 in FIGS. 4and 5, that lies between adjacent protuberances 42. The effective crosssectional shape of troughs 44, as can be best seen in FIG. (which showsa cross section of element 30 of which a plan view is given in FIG. 4),is substantially an inverted triangle.

A series of slightly deeper troughs 45 is formed between adjacentprotuberances 42 extending at right angles to troughs 44. As best seenin FIG. 6, the bottom of each trough 45 is formed by portions ofstraight strands 40, with successive protuberances 42 on each side ofthe trough forming the tops of the trough. As seen in FIG. 6, theeffective cross sectional shape of troughs 45 may be characterized as ashallow U-sha'pe.

As shown in FIG. 4, troughs 44 and protuberances 42 alternate in onedirection across the surface of foraminous portion 30 of backing means16. FIG. 4 also shows that troughs 45 and protuberances 42 alternate ina direction perpendicular to troughs 44. Hence a plurality of troughsand a plurality of protuberances alternate in both the longitudinal andtransverse directions across the surface of foraminous portion 30 ofbacking means 16.

To produce satisfactory rearrangement of fibers into yam-like bundles ofclosely associated and substantially parallel fiber segments positionedin troughs 44 and 45, the vertical distance between the tops ofprotuberances 42 and the bottoms of the immediately adjacent troughsshould be at least about three times, generally no more than about 30times, and preferably about 10 times, the average diameter of the fibersin the layer of fibrous starting material. For troughs 44, this distanceis the vertical distance indicated in FIG. 5 by the pair of dashed linesthat pass, respectively, through the tops of protuberances 42 and thecrossing points 43 that define the troughs. The vertical distance fromthe bottom of each trough 45 to the tops of protuberances 42, on theother hand, is somewhat larger, being shown by FIGS. 5 and 6 to be equalto the diameter of a strand 41.

In the embodiment shown, each protuberance 42 has a directional effectin one direction because of its proximity to other similar protuberanceson foraminous portion 30 of the backing means, and in the otherdirection for the same reason and in addition because of the crosssectional shape of the protuberance. Thus, each protuberance 42 iseffective in both the longitudinal and transverse directions. As anexample, the protuberance 42 to which the designator line runs in theupper left hand comer of FIG. 4, through cooperation with theprotuberance 42 to which the designator line runs in the left centralpart of the bottom of that same figure, is effective as a protuberancethat defines one wall of trough 44 running vertically down the middle ofthe figure. At the same time, the first named protuberance 42, throughcopperation with protuberance 42 to which the designator line runs inthe upper right hand part of FIG. 4, is effective as a protuberance thatdefines one wall of trough 45 running horizontally across the middle ofthe figure. In addition, the cross sectional shape of each protuberance42 (as best seen in FIGS. 4 and 6) exerts a directional effect on thefibers of the fibrous starting material by its sharper definition of theside walls of each trough extending horizontally across FIG. 4, i.e., onthe side walls of each trough 45.

At the point of closest spacing of each pair of immediately adjacentbarrier regions or discontinuous imperforate portions 31 of backingmeans 16, each continuous deflecting region or interconnectingforaminous portion 30 is wide enough to include at least one dispersalpoint or protuberance 42 and a fiber accumulating zone or trough 44 or45 on each side thereof. In the embodiment of FIGS. 2 and 3, each pairof imperforate portions 31 include between them at their point ofclosest spacing about five protuberances 42 and their associated troughsor fiber accumulating zones.

Three portions of rearranging fluid. The directions the projectedstreams of rearranging fluid take as they move into and through thefibrous web determine the types of forces applied to the fibers and, inturn, the extent or rearrangement of the fibers. Since the directionsthe streams of rearranging fluid take as thy move through the fibrouslayer are determined in part by the pattern of the solid wires that makeup foraminous portions 30 of backing means 16, and in particular thepattern of protuberances and troughs distributed across the surface offoraminous portions 30, it follows that the pattern of these areas helpsdetermine the patterns of holes or other areas of low fiber density inthe resultant fabric.

As is seen from FIG. 4, first portions of the streams of rearrangingfluid that have been projected into the fibrous web strike the wires ofwoven screen 30, at protuberances 42 or at other portions of the wire,and are deflected sidewise before they pass out of the rearranging zonethrough openings 46. The streams of rearranging fluid that strikeprotuberance 42 in the upper left hand part of FIG. 4, for example,leave the fiber rearranging zone through openings 46a, 46b, 46c and 46din the respective sectors or quadrants of the area surrounding thatprotuberance.

FIGS. 2 and 3 show that second portions of the rearranging fluidprojected into the layer of starting material strike discontinuousimperforate portions 31 of backing means 16, and are deflected sidewiseinto the areas above foraminous portions 30, where they are mingled withthe first portions of rearranging fluid and are passed out of therearranging zone though openings 46.

Third portions of the rearranging fluid projected into the fibrous webpass directly through openings 46 in foraminous backing portion 30,without being deflected either by protuberances 42 or imperforateportions 31.

Flow of first portions of rearranging fluid through deflecting regions.The dotted lines in FIGS. 5 and 6 give a schematic showing of the pathfollowed by a stream of rearranging fluid 47 that is directed into thelayer of fibrous starting material, in a direction perpendicular to thatlayer, to strike protuberance 42 in the upper left hand corner of FIG.4. As is seen, the stream of fluid is deflected downwardly and outwardlyaway from its perpendicular direction of entry into the fiberrearranging zone, and then moves out of the rearranging zone through theopenings between wires 40 and 41.

The flow of streams of rearranging fluid after being deflected sidewiseupon striking protuberances 42 of foraminous portions 30 of backingmeans 16 produces sets of counteracting components of force that act inthe plane of the web until the fluid passes out through the foramina inportions 30. The counteracting fluid forces in each of these sets workin conjunction with one another to rearrange fiber segments intoyarn-like I bundles positioned in troughs 44 and 45 of portion 30 ofbacking means 16. Some of these yarnlike bundles of fiber segments liein fiber accumulating zones in peripheral portions of foraminousportions 30 adjacent discontinuous imperforate portions 31 of backingmeans 16, while some lie in troughs or fiber accumulating zones betweenone protuberance 42 and another protuberance that is parallel andimmediately adjacent to it.

When the layer of fibrous starting material is first positioned in thatpart of the fiber rearranging zone located above foraminous portion 30of backing means 16, and before a rearranging fluid has been directedinto the layer, the fibrous web of course lies upon the tops ofprotuberances 42. After fiber arrangement has proceeded under the impactof the streams of rearranging fluid, the fibers are moved down thesloping sides of protuberances 42 into troughs 44 and 45. At thisjuncture, the layer of rearranged fibers that comprises the nonwovenfabric ordinarily lies largely, if not altogether, below the tops ofprotuberances 42.

FIGS. 7 and 8 provide schematic representations of the flow of streamsof rearranging fluid 47 that has been described in connection with FIGS.4 through 6. As explained above, in the practice of this invention thelayer of fibrous starting material is supported in a fiber rearrangingzone in which fiber movement in directions parallel to the plane of thefibrous material is permitted in response to applied fluid forces. Thefiber rearranging zone has an entry side and an exit side, and issubdivided into barrier regions 31 arranged in a discontinuous patternand deflecting regions 30 that are continuous and lie between andinterconnect the barrier regions. FIGS. 7 and 8 depict a part of adeflecting region 30.

In FIGS. 7 and 8, the fiber rearranging zone is indicated as beingdefined by foraminous portion 30 of backing means 16. Streams ofrearranging fluid are projected into the fibrous layer as thussupported, in a direction perpendicular to said layer, substantiallyuniformly and continuously across the surface of the layer. In FIGS. 7and 8, streams 47 represent first portions of those rearranging streamsthat take a particular path through the fiber rearranging zone.

First portions 47 of the rearranging fluid are passed through initialpart 48 of the rearranging zone, as the fibrous layer lies in the zone.The streams of fluid 47 are passed toward dispersal points 42 lyingadjacent the exit side of the rearranging zone, two of which dispersalpoints are shown for illustrative purposes in FIGS. 7 and 8.

At each dispersal point 42, streams of rearranging fluid 47 aredeflected diagonally and downwardly away from the perpendiculardirection of entry of streams 47 into the fibrous starting material,into the area immediately surrounding each dispersal point 42. In FIGS.7 and 8, fluid stream 47 that is directed toward dispersal point 42 inthe upper left hand portion of FIG. 8 is directed upon deflection intosectors or quadrants 46a, 46b, 46c and 46d of the area surrounding thatdispersal point.

A few of the fiber segments of the fibrous starting material that lie indeflecting region 30 of the rearranging zone remain, after treatmentwith streams of rearranging fluid, in substantially the positions theyoccupied by random chance in the starting layer. Most of the fibersegments lying in the deflecting region, however, are moved by thedeflection of rearranging fluid just described into the area surroundingthat dispersal point 42 at which each fluid stream 47 was deflected.

The fiber segments moved by deflected streams of rearranging fluid 47are positioned in yarn-like bundles of closely associated andsubstantially parallel fiber segments in fiber accumulating zones 44 and45 in the area surrounding each dispersal point 42. As an example, fibersegments that are moved so that they extend between areas 46a and 46b ofFIG. 8 are positioned there in fiber accumulating zone 44 which extendsvertically in that figure between the two dispersal points 42, lyingadjacent each other, that are shown in FIG. 8. Likewise, fiber segmentsthat are moved so that they extend between areas 461; and 460 arepositioned in fiber accumulating zone 45 which extends horizontally inFIG. 8, and so on. Fiber accumulating zones 44 and 45 correspond totroughs 44 and 45 shown in FIGS. 4 through 6. The yarn-like bundles offiber segments positioned in the fiber accumulating zones form a patternof yarn-like bundles corresponding to the pattern of the fiberaccumulating zones, which in turn is determined, among other things, bythe position of the various dispersal points 42 throughout the fiberrearranging zone.

The deflected portions of rearranging fluid 47 are then passed out ofthe fiber rearranging zone through spaced exits such as 46a through 46d,and similar exit areas, in FIGS. 7 and 8. At the same time, otherportions of rearranging fluid that were projected into the layer offibrous starting material, for example those portions entering the entryzone in direct registry with exit 4612, are moved directly to andthrough the exits on the exit side of the rearranging zone withoutpassing through a dispersal point 42 to be deflected from theperpendicular direction at which they entered the fibrous startinglayer.

In the embodiment shown diagrammatically in FIGS. 4 through 6 and in theschematic representations of FIGS. 7 and 8, the spaced exits on the exitside of the rearranging zone are located in the fiber accumulatingzones.

Flow of second portions of rearranging fluid through barrier regions.The directions taken by the second portions of the streams ofrearranging fluid, which are projected into the fibrous startingmaterial lying in the barrier regions of the fiber rearranging zone, areof course also important. The directions those portions of therearranging fluid take as they move into and through the fibrous webdetermine the types of forces applied to the fibers that lie in thebarrier regions, and, in turn, help determine the extent ofrearrangement of the fibers throughout the barrier regions, and thushelp determine the pattern of holes or other areas of low fiber densityin the resultant fabric.

The second portions of the rearranging fluid which are projected into abarrier region for example, each part of the rearranging zone overlyingan area 31 where backing means 16 is imperforate are deflected sidewiseout of the barrier region into adjacent deflecting regions. Thus, suchstreams strike imperforate portions 31 in FIG. 2, to be deflectedsidewise and effect movement of fiber segments transverse to thedirection of travel of the projected streams.

This fluid flow pushes fiber segments off imperforate portions 31 toposition the segments in the above mentioned yam-like bundles of fibersegments in areas adjacent the periphery of those imperforate portions,and elsewhere in the deflecting regions overlying foraminous portions 30of the backing means. In some instances, the fluid may push all fibersegments off the imperforate portions of the backing means, while inother instances some fiber segments are left to span those portions.

' Flow of third portions of rearranging fluid through deflectingregions. As indicated above, the passage of rearranging fluid throughthe fiber rearranging zone and the layer of fibrous starting materialsupported therein is completed by the flow of third portions of thefluid through the deflecting regions of the rearranging zone.

As is seen from FIG. 4, third portions of rearranging fluid that areprojected into the fibrous web in a direction perpendicular to the planeof the web (i.e., the plane of the drawing in that figure) pass throughthe fibrous layer and, after being intermingled with the first andsecond portions of fluid discussed above, pass directly out of the fiberrearranging zone through spaced exits such as openings 46a, 46b, 46c and46d. These third portions of fluid do not strike protuberances 42 to bedeflected sidewise, and thus do not pass through any dispersal points inthe deflecting region. Likewise, since they do not enter the barrierregions of the fiber rearranging zone, they do not strike imperforateportions 31 of backing means 16.

The rearranged web or fabric produced by the practice of this inventionmay be treated with an adhesive, dye or other impregnating, printing, orcoating material in a conventional manner. For example, to strengthenthe rearranged web, any suitable adhesive bonding materials or bindersmay be included in an aqueous or non-aqueous medium employed as therearranging fluid. Or an adhesive binder may, if desired, be printed onthe rearranged web to provide the necessary fabric strength.Thermoplastic binders may, if desired, be applied to the rearranged webin powder form before, during or after rearrangement, and then fused tobond the fibers.

The optimum binder content for a given fabric according to thisinvention depends upon a number of factors, including the nature of thebinder material, the size and shape of the binder members and theirarrangement in the fabric, the nature and length of the fibers, totalfiber weight, and the like. In some instances, because of the strengthof the fibers used or the tightness of their interentanglement in therearranged web or fabric, or both factors, no binder at all need beemployed to provide a usuable fabric.

The following is an illustrative example of the use of the method andapparatus of this invention to produce a patterned nonwoven fabric:

EXAMPLE In apparatus as illustrated in FIG. 1, a web 15 of looselyassembled fibers, such as may be obtained by carding, is fed betweenwet-out rolls 6 and 7, and from there onto endless backing means 16. Theweb weight is about 400 grains per square yard, and its fiberorientation ratio approximately 7 to l in the direction of travel. Theweb contains viscose rayon fibers approximately 1 9/16 inches long, of1% denier.

Foraminous portions 30 of backing means 16 are comprised of a wovenmetal screen of approximately 8 X 16 mesh or substantially 128 openingsper square inch. The top of each protuberance 42 on the backing meansrises above the bottoms of troughs 44 immediately adjacent to it byapproximately 0.018 inch, or about 12 times the 0.0015 inch averagediameter of the 1% denier fibers of the starting material. They riseapproximately 0.026 inch above the bottoms of troughs 45, or about 18times the average fiber diameter.

The distance measured in one direction across foraminous portions 30 ofbacking means 16 between the top of one protuberance 42 and the top ofthe protuberance immediately adjacent to it is about 0.063 inch, and inthe other direction about 0.125 inch. These distances are equal,respectively, to approximately 42 and 84 times the average diameter ofthe fibers of the fibrous starting material.

Discontinuous imperforate portions 311 of backing means 16 are smoothround metal members of a diameter of approximately one-fourth inch andhaving a cross sectional shape similar to that shown in FIG. 3. They aredistributed over the area of backing means 16 in a diamond pattern, witha space of approximately threesixteenths inch from each portion 31 tothe nearest other portion 31 in a diagonal direction. Central portions32 of elements 31 rise about 0.012 inch above the plane of the topsurface of continuous foraminous portions 30 of the backing means, andedge portions 33 rise about 0.010 inch above that plane.

The distances between one fiber accumulating zone or trough and the zoneor trough immediately adjacent and parallel to it are the same, in thetwo directions across foraminous portions 30, as the distances betweenadjacent protuberances. Hence the 0.25 inch width of each imperforateportion 31 is between about two and about four times the distancebetween trough centers.

In the practice of this invention, water is projected from nozzles 23against fibrous web in a direction perpendicular to the plane of theweb, to pass through the fibrous layer and through backing means 16.

After given portions of backing means 16 and fibrous web 15 pass throughthe rearranging zone, in which streams of water are directed againstthem as just described, the movement of the upper reach of endless belt16 (to the right as seen in FIG. ll) brings the rearranged fabric todoffer roll 29a and guide rolls 29b and 290, from whence it leaves theapparatus.

With the conditions indicated, good fiber rearrangement and bundling areobtained, and an excellent nonwoven fabric such as shown in thephotomicrograph of FIG. 9, which has a plurality of patterns of holes orother areas of low fiber density that alternate and extend throughoutthe fabric, is produced.

Nonwoven fabric 50 of FIG. 9 is shown with an original enlargement offive times in the photomicrograph of FIG. 10. As seen in the latterfigure, fabric 50 contains a first pattern of areas of low fiber density51, each of which overlies a discontinuous imperforate portion 31 ofbacking means 16. Each area 51 is defined by yarn-like bundles 52 ofclosely associated and substantially parallel fiber segments, which liein fiber accumulating zones located in the peripheral portions of thedeflecting regions of the fiber rearranging zones, as for example in theperipheral portions of each foraminous portion 30 where it abuts theperimeter of discontinuous imperforate portions 31. Each area of lowfiber density 51 contains a few scattered fiber segments that bridgeacross the area.

In addition, nonwoven fabric 50 contains a second pattern of areas oflow fiber density in the form of holes 53, arranged in accordance withthe pattern of arrangement of protuberances 42 of foraminous portions 30of backing means 16. Each of these areas 53 is defined by yam-likebundles 54 of closely associated and substantially parallel fibersegments, which lie in fiber accumulating zones located betweenimmediately adjacent dispersal points, as for example immediatelyadjacent protuberances $2 in foraminous portions 30 of backing means 16.In the fabric shown, each hole 53 is substantially free of any fibersegments.

Each area of low fiber density 51 appears from FIG. 10 to beapproximately 40 times the size of each area of low fiber density 53, oralittle bit larger. This is consistent with the relative size ofdiscontinuous imperforate portions 31 and protuberances 42 of foraminousportions 30 that are included in the apparatus with which the fabric ofFIGS. 9 and 10 was made.

Each pair of immediately adjacent large areas of low fiber density 51 isseparated by at least one of the smaller holes, such as those designated53' in FIG. 10. To produce this result, the width of interconnectingforaminous portions 30 of backing means 16 at their narrowest parts (or,in other words, the closest diagonal spacing between imperforateportions 31 of the backing means, which is about 3/16 inch or 0.188inch) is sufficient to include at all points around the perimeter ofeach imperforate portion 30 at least one protuberance 42 and in mostparts of the rearranging zone two protuberances 42 with associated fiberaccumulating zones or troughs 44 and 45.

The above detailed description has been given for cleamess ofunderstanding only. No unnecessary limitations should be understoodtherefrom, as modifications will be obvious to those skilled in the art.

I claim:

1. Apparatus for producing a patterned nonwoven fabric having aplurality of patterns of areas of low fiber density that alternate andextend throughout said fabric, from a layer of fibrous starting materialwhose individual fibers are in mechanical engagement with one anotherbut are capable of movement under applied fluid forces, which comprises:backing means for said layer of fibrous starting material, said meanshaving portions which are imperforate and portions which are foraminous,said imperforate portions being discontinuous and said foraminousportions being continuous and interconnecting the discontinuousimperforate portions, said continuous foraminous portions comprising atleast 10 percent of the total area of the backing means, said foraminousportions having a plurality of protuberances and troughs alternatingacross the surface thereof in both the longitudinal and transversedirections, the tops of said protuberances rising above the bottoms ofsaid troughs by a distance of at least .005 inch, the width of eachtrough being at least 0.025 inch, each of said discontinuous imperforateprotions extending along the surface of the backing means a distance atleast about twice the horizontal distance from the center of one of saidtroughs to the center of the trough immediately adjacent and parallel toit, and each pair of immediately adjacent discontinuous imperforateportions spanning between them at least one of said protuberances and atleast part of one of said troughs on each side of said one protuberance;means for moving said backing means, with a layer of fibrous startingmaterial positioned thereon, through a rearranging zone; means forprojecting streams of rearranging fluid against said fibrous layersubstantially uniformly and continuously across the surface thereof topass through said layer, some of said fluid streams striking saidimperforate portions of the backing means and other of said fluidstreams striking said protuberances on the backing means, all to bedeflected thereby in sidewise directions and all of said fluid streams,together with other streams of fluid that do not strike the backingmeans, passing through and beyond said foraminous portions of thebacking means; and means to apply vacuum on the side of said backingmeans opposite to said fibrous layer to assist in moving all saidrearranging fluid through the fibrous layer and in rearranging thefibers of said layer.

2. The apparatus of claim 1 in which each of said discontinuousimperforate portions of the backing means rises above the plane of thetops of said foraminous portions of the backing means by a distance ofat least 1/64 inch, with the central portion of said discontinuousportion rising higher than the edge portions thereof.

3. The apparatus of claim 1 in which the width of each of saiddiscontinuous imperforate portions of the backing means, measured ineach direction, is equal to at least about three times the horizontaldistance from the center of one of said troughs to the center of thetrough immediately adjacent and parallel to it.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,750,236 Dated August 7, 973,

Inventor (5) Frank- Kalwaites It is certified that error appears in theabove-identified patent and thatsaid Letters Patent are hereby correctedas shown below:

r. Abstract: Next to last line insert "the" before .1 protuberances.

In Column 4, line 3 L "arrangement" should. read "rearrangement" InColumn 6, line 1 "polyanides" should read "polyamides" in Column 7, line35 "with" should read "With" In Column 7, line 41. "material. or" shouldread "material,

In Column 9, line 57 "the" should. read "the" In colunn 10, line 21"fibe" should read "five" n In ooiumn 1o, liheAg delete "109" "In Column13, line l2"thy" should be "they" In Column 1? line 38- "though" --Y-should read "through" In Columnlfl, line 10 "arrangement" should read"rearrangement" 1 Signed and .seal ed this 15th day of October 1974.

(SEAL) Attest:

'nccoy GIBSON, JR. 1-

l L 0. MARSHALL DANN e Attesting Officer Commissioner of Patents

1. Apparatus for producing a patterned nonwoven fabric having aplurality of patterns of areas of low fiber density that alternate andextend throughout said fabric, from a layer of fibrous starting materialwhose individual fibers are in mechanical engagement with one anotherbut are capable of movement under applied fluid forces, which comprises:backing means for said layer of fibrous starting material, said meanshaving portions which are imperforate and portions which are foraminous,said imperforate portions being discontinuous and said foraminousportions being continuous and interconnecting the discontinuousimperforate portions, said continuous foraminous portions comprising atleast 10 percent of the total area of the backing means, said foraminousportions having a plurality of protuberances and troughs alternatingacross the surface thereof in both the longitudinal and transversedirections, the tops of said protuberances rising above the bottoms ofsaid troughs by a distance of at least .005 inch, the width of eachtrough being at least 0.025 inch, each of said discontinuous imperforateprotions extending along the surface of the backing means a distance atleast about twice the horizontal distance from the center of one of saidtroughs to the center of the trough immediately adjacent and parallel toit, and each pair of immediately adjacent discontinuous imperforateportions spanning between them at least one of said protuberances and atleast part of one of said troughs on each side of said one protuberance;means for moving said backing means, with a layer of fibrous startingmaterial positioned thereon, through a rearranging zone; means forprojecting streams of rearranging fluid against said fibrous layersubstantially uniformly and continuously across the surface thereof topass through said layer, some of said fluid streams striking saidimperforate portions of the backing means and other of said fluidstreams striking said protuberances on the backing means, all to bedeflected thereby in sidewise directions and all of said fluid streams,together with other streams of fluid that do not strike the backingmeans, passing through and beyond said foraminous portions of thebacking means; and means to apply vacuum on the side of said backingmeans opposite to said fibrous layer to assist in moving all saidrearranging fluid through the fibrous layer and in rearranging thefibers of said layer.
 2. The apparatus of claim 1 in which each of saiddiscontinuous imperforate portions of the backing means rises above theplane of the tops of said foraminous portions of the backing means by adistance of at least 1/64 inch, with the central portion of saiddiscontinuous portion rising higher than the edge portions thereof. 3.The apparatus of claim 1 in which the width of each of saiddiscontinuous imperforate portions of the backing means, measured ineach direction, is equal to at least about three times the horizontaldistance from the center of one of said troughs to the center of thetrough immediately adjacent and parallel to it.